Very silly question: looks like 4.11 and 4.11m is the same. Is this true?. As far as I can remember (but not sure) always there is a "basic" patch and a "m added" patch.
I downloaded 4.11, installed and just before my game crashes I read 4.11m. Am I doing something wrong?, there is a 4.11 without m?, where is it?.
Started from 4.10.01m running ok, installed hotfix DT.dll but it crashes at start up.
Any advice will be welcome.

The m designation goes back to Pacific Fighters when they first merged the IL-2 and Pacific Fighters lines. Pacific Fighters could be played as a stand-alone or merged with IL-2 Forgotten Battles + Aces Expansion Pack.

IL-2 Sturmovik 1946 has always had the m designation starting with the DVD which is v4.07m.

IL-2 Sturmovik 1946 content.

IL-2 Forgotten Battles (v1.0 - v1.22)

Aces Expansion Pack (v2.0 - v2.04)

Pacific Fighters - (v3.0m - v4.04m)

PE-2 Peshka - Addon (v4.05m)

Sturmoviks over Manchuria - Addon (v4.06m)

46 - addon (v4.07m) which later became the IL-2 Sturmovik 1946 package that included all of the content and kept the v4.07m designation.

Pacific Fighters, PE-2 Peshka, Sturmoviks over Manchuria, 46 were all Russian Rocket Games Studios projects. A company that involved luthier (Now heading up the Cliffs of Dover project) and Starshoy (The creator of DGen and NGen).

In the future these patching guide at M4T should help you with the patching process.